Contrary to the claims of most paleontologists, researchers from University of Kansas and Northeastern University in China say that bird flight evolved up in the trees, and flight tests of a model of the four-winged gliding raptor called microraptor lend credence to their theory. "The controversy was that these animals couldn't spread their hind-wings to glide," said Burnham. "But we've been able to articulate the bones in their hip socket to show that they could fly." The new flight model created by Martin and Burnham comes directly from a skeleton composed of casts of the original bones of a microraptor and the preserved impressions of feathers from specimens in Chinese museums. read more